A conventional mounting structure for a speaker with respect to a panel is described in Patent Document 1 below. According to the structure described in this document, a speaker is mounted directly to the mounting base on the back surface of a panel by using engagement tabs and grooves or by using screws. Such a mounting structure for a speaker is employed in e.g. a flat panel display of a personal computer.    Patent Document 1: Japanese Lain-open Patent Publication No. H09-163481
However, with the above-described conventional structure, the speaker cannot be completely fixed to the mounting base by the simple engagement of the tabs with the grooves. As a result of such incomplete fixation, undesired chattering noise may be made due to vibrations generated when the speaker produces sounds.
The other mounting structure, in which the speaker is fixed with screws, requires individual tightening for each of the screws. Thus, this structure is disadvantageous in that the speaker mounting process is time-consuming.